How to Grow and Care for Hoya Kalimantan

The Hoya Kalimantan, also known as Hoya callistophylla sp. Kalimantan, is a plant sought after by collectors for its visually striking foliage. Its most defining feature is its large, lime green leaves contrasted with dark green veins, which can grow up to twelve centimeters long. Native to the Kalimantan region of Borneo, this plant is an epiphyte, meaning it climbs on other trees in its natural habitat. This vining nature makes it a great choice for hanging baskets or for training up a trellis.

Hoya Kalimantan Care Guide

Light

Proper lighting is a significant factor in the health of Hoya Kalimantan. This plant thrives in bright, indirect light, which mimics the dappled sunlight it would receive in a tropical forest. An east-facing window is often ideal, providing gentle morning sun. Placing the plant in brighter light can bring out a reddish hue in the foliage, but avoid direct, harsh sunlight, as this can scorch the leaves.

Water

When watering your Hoya Kalimantan, avoid both under-watering and over-watering. A reliable method is to allow the top few centimeters of the growing medium to dry out completely before watering again. You can also check the leaves for firmness; if the normally succulent leaves feel slightly soft or pliable, it’s a good indication the plant is ready for water. Overwatering can lead to root rot, so ensure the soil is not perpetually damp.

Soil

Hoya Kalimantan requires a growing medium with excellent drainage to prevent its roots from becoming waterlogged. Standard potting soil is often too dense and can retain too much moisture, leading to root rot. A chunky, airy mix is far more suitable, which you can create by combining potting soil with amendments like orchid bark and perlite. A common recipe is a blend of 50% potting soil with 25% orchid bark and 25% perlite.

Temperature and Humidity

This tropical native appreciates warm and humid conditions. It grows best in temperatures ranging from 18 to 26 degrees Celsius. While it can tolerate average household humidity, providing higher humidity of over 60% will result in more robust growth. You can increase ambient moisture by grouping it with other plants or placing it near a humidifier.

Fertilizer

To support its growth during the spring and summer, a regular feeding schedule is beneficial. Fertilize your Hoya Kalimantan monthly using a diluted general houseplant fertilizer. A balanced liquid fertilizer diluted to half the recommended strength is sufficient to provide the nutrients it needs. Reduce feeding during the fall and winter when the plant’s growth naturally slows down.

Encouraging Hoya Kalimantan Blooms

Achieving blooms on a Hoya Kalimantan is driven by providing the right conditions. Plant maturity is a primary factor, as young plants are less likely to flower than established ones. Adequate light is also a trigger, and allowing the plant to become slightly root-bound in its pot can encourage it to shift energy to flower production.

The flowers grow in clusters, known as umbels, which can contain up to 27 individual blooms. Each flower is a buttery-yellow color with red-maroon tips and a creamy-white center, or corona. The flowers also release a pleasant fragrance often described as a combination of lemongrass and citrus. Remember not to remove the small stalks, or peduncles, from which the flowers emerge, as Hoyas can re-bloom from the same spot.

How to Propagate Hoya Kalimantan

Propagating Hoya Kalimantan is done using stem cuttings from a healthy, mature specimen. Select a healthy vine and ensure your cutting has at least one node—the small bump on the stem where leaves and roots emerge. A cutting with two or three nodes increases the chances of successful rooting.

Once you have taken your cutting, you can root it in several different mediums. Placing the cutting in a glass of water is a popular method that allows you to watch the roots develop. Another option is to plant the cutting in a pot of moist sphagnum moss, perlite, or a well-draining soil mix. Providing warmth and humidity will help encourage faster root development.

Common Hoya Kalimantan Problems

One of the most common problems is yellowing leaves, which is a sign of overwatering. If you notice this, check the soil’s moisture level and allow it to dry out more thoroughly between waterings. Ensure the pot has adequate drainage to prevent water from sitting at the roots.

Leggy growth, characterized by long stems with few leaves, indicates that the plant is not receiving enough light. Relocating your hoya to a spot with brighter, indirect light will encourage more compact foliage. Pests can also be an issue, with mealybugs and spider mites being the most common. Treat the plant by wiping the leaves with a cotton swab dipped in rubbing alcohol or by using neem oil.